size=int(input("请输入棋盘的大小:"))
for i in range(size):
    for j in range(size):
        if i==0 and j==0:
            print("┌",end='')
        elif i==0 and j==size-1:
            print("┐",end='')
        elif i==size-1 and j==0:
            print("└",end='')
        elif i==size-1 and j==size-1:
            print("┘",end='')
        elif j==0: 
            print("├",end='')
        elif i==size-1:
            print("┴",end='')
        elif j==size-1:
            print("┤",end='')
        elif i==0:
            print("┬",end='')
        else:
            print("┼",end='')
    print('')